Multiparameter analysis methods. By gating on different subpopulations, their properties with regard to additional parameters can be determined. Most commercial flow cytometers can measure between 4 and 8 fluorescence signals in addition to forward scatter (FSC) and side scatter (SSC). As an illustration of the compexity of multiparameter data, the graph below shows a sample of yeast cells stained for viability with ethidium bromide. A: ethidium bromide fluorescence (FL2) against cell size (FSC). B: size (FSC) against granularity characteristics (SSC). Cells marked in panel A as belonging to distinct subpopulations are identified by the same colors in panel B.